Answer:
C. The Japanese surprise attack on the Russian navy at Port Arthur.
Explanation:
The war developed from Russia's and Japan's rivalry for dominance in Korea and Manchuria. After the First Sino-Japanese War, Japan acquired the Liaodong Peninsula from China, but European powers forced Japan to return it. China subsequently leased it to Russia.
Through this, the war affected the stability of Europe, Russia in particular, the equilibrium between the United States and Japan, and the territorial status quo in Northeast Asia. The Russo-Japanese War did not cause any instant or visible uprising in Europe but its ultimate impact on this continent was devastating.